Display panel, and frame sealant application device and application method thereof

ABSTRACT

A display panel, a sealant coating device and a method for sealant coating are provided. The display panel includes a display area and a peripheral area and further includes oleophobic sealant provided in the peripheral area on a side near the display area and hydrophobic sealant provided in the peripheral area on a side away from the display area and surrounding the oleophobic sealant.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the priority to the Chinese patentapplication No. 201710194136.4 filed on Mar. 28, 2017 to SIPO andentitled “a display panel, and a sealant coating device and a method forsealant coating,” which is incorporated herein by reference in itsentirety.

TECHNICAL FIELD

Embodiments of the present disclosure relate to a display panel, asealant coating device and a method for sealant coating.

BACKGROUND

As an important material used for production of liquid crystal displaypanels, the sealant is operable to bond a lower substrate and an uppersubstrate firmly together and protect the entire overlay of variouscircuit wiring on the lower substrate, i.e. the substrate on which thinfilm transistors (TFTs) are arranged in an array, very well fromcorrosion.

SUMMARY

Embodiments of the present disclosure provide a display panel, a sealantcoating device and a method for sealant coating.

Embodiments of the present disclosure employ the following technicalproposals.

In a first aspect, a display panel is provided by embodiments of thepresent disclosure, comprising: a display area and a peripheral area; anoleophobic sealant provided in the peripheral area on a side near thedisplay area; and a hydrophobic sealant provided in the peripheral areaon a side away from the display area and surrounding the oleophobicsealant.

For example, the oleophobic sealant comprises a matrix sealant materialand particles dispersed in the matrix sealant material, the dispersedparticles having oleophobic first functional groups on their surfaces.

For example, the oleophobic first functional group comprises at leastone of —OH, —CHO, —COOH and —NH₂.

Optionally, the hydrophobic sealant comprises a matrix sealant materialand particles dispersed in the matrix sealant material, the dispersedparticles having hydrophobic second functional groups on their surfaces.

For example, the hydrophobic second functional group comprises at leastone of —C_(n)H_((2n+1)), —CH═CH₂, —C₆H₅, a halogen atom and —NO₂, wheren is a positive integer.

Optionally, the material of the dispersed particles includes any ofsilicon dioxide, silicon and aluminum oxide (Al₂O₃).

Optionally, the dispersed particles are in a spherical shape.

In a second aspect, a device for sealant coating is provided by anembodiment of the present disclosure, comprising a first sealantsupplying container, a second sealant supplying container and a sprayhead. The spray head comprises a first accommodation chamber, a secondaccommodation chamber and a slit opening. The first accommodationchamber and the second accommodation chamber are in intercommunicationat the area near the slit opening. The first sealant supplying containerand the second sealant supplying container are in communication withends of the first accommodation chamber and the second accommodationchamber away from the slit opening and configured to contain oleophobicsealant and hydrophobic sealant, respectively.

Optionally, the device for sealant coating further comprises a pressurecontroller to control the feeding amount of sealant from the firstsealant supplying container and/or the second sealant supplyingcontainer.

In a third aspect, a coating method using the device for sealant coatingis provided in an embodiment of the present disclosure, comprising:allowing a side of the second accommodation chamber of the spray head toface the display area of the first substrate in the display panel;allowing a side of the first accommodation chamber of the spray head toface away from the display area; and controlling the spray head to spraythe sealant along the peripheral area of the first substrate so as toform the hydrophobic sealant in the peripheral area and on the side nearthe display area and form the oleophobic sealant in the peripheral areaon the side away from the display area and surrounding the hydrophobicsealant.

BRIEF DESCRIPTION TO THE DRAWINGS

Embodiments of the present disclosure will be described in more detailbelow with reference to accompanying drawings to allow an ordinary skillin the art to more clearly understand embodiments of the presentdisclosure, in which:

FIG. 1 is a flowchart illustrating a process for sealant coating;

FIG. 2 is a structural diagram of a display panel provided in anembodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating effects of an oleophobicsealant and a hydrophobic sealant in a display panel provided in anembodiment of the present disclosure;

FIG. 4 is a schematic diagram illustrating contact angles of a type ofoleophobic sealant provided in an embodiment of the present disclosure;

FIG. 5 is a schematic diagram illustrating contact angles of a type ofhydrophobic sealant provided in an embodiment of the present disclosure;

FIG. 6 is a schematically structural diagram of two types of dispersedparticles provided in an embodiment of the present disclosure;

FIG. 7 is a schematically structural diagram of a device for sealantcoating provided in an embodiment of the present disclosure.

DETAILED DESCRIPTION

Technical solutions of the embodiments will be described in a clearlyand fully understandable way in connection with the drawings related tothe embodiments of the disclosure. It is apparent that the describedembodiments are just a part but not all of the embodiments of thedisclosure. Based on the described embodiments herein, a person ofordinary skill in the art can obtain other embodiment(s), without anycreative work, which shall be within the scope of the disclosure.

Unless otherwise defined, all the technical and scientific terms usedherein have the same meanings as commonly understood by one of ordinaryskill in the art to which the present disclosure belongs. The terms,such as “first,” “second,” or the like, which are used in thedescription and the claims of the present application, are not intendedto indicate any sequence, amount or importance, but for distinguishingvarious components. Also, the terms, such as “comprise/comprising,”“include/including,” or the like are intended to specify that theelements or the objects stated before these terms encompass the elementsor the objects and equivalents thereof listed after these terms, but notpreclude other elements or objects. The terms, “on,” “under,” “a side,”“another side,” or the like are only used to indicate relative positionrelationship, and when the absolute position of the object which isdescribed is changed, the relative position relationship may be changedaccordingly.

Structural dimensions involved in embodiments of the present disclosurerange generally in order of magnitude from nanometer to millimeter(nm˜mm), and for purpose of clear explanation, dimensions of structuresin the accompanying drawings of embodiments of the present disclosureare exaggerated and not representative of actual dimensions.

Traditional sealant is mainly composed of resin and initiator. As shownin FIG. 1, a coating process for the sealant includes spray the sealantonto the peripheral area of the lower substrate using spray head,dripping liquid crystals onto the display area defined by the sealant,assembling the lower substrate with an upper substrate, pre-curing thesealant using the UV (Ultraviolet) irradiation, and finallythermo-curing the sealant (now shown in FIG. 1).

It has been noticed by the present inventors that the sealant isincreasingly close to the display area as the bezels of display productsare designed to be increasingly narrow. After assembling of the lowerand upper substrates, the liquid crystal molecules may diffuse to spreadout due to their fluidity. If the liquid crystal molecules come intocontact with the sealant without being pre-cured by UV, the sealant maybe punctured and the liquid crystal may be contaminated, leading toimage flickering (FLK) during display OF the liquid crystal displaypanel and thus affecting display quality of the panel. Moreover, asbezels of display products are becoming narrower, the coating width ofsealant is becoming smaller and moisture may intrude through the sealantto corrode circuit wiringS on the TFT substrate during subsequent usage,leading to abnormal display.

As shown in FIG. 2, an embodiment of the present disclosure provides adisplay panel 01 including a display area (indicated by A in the figure)and a peripheral area (indicated by S in the figure). The display panel01 includes an oleophobic sealant 10 disposed in the peripheral area onthe side near the display area and a hydrophobic sealant 20 disposed inthe peripheral area on the side away from the display area andsurrounding the oleophobic sealant 10.

It is to be noted that the display panel 01 further includes a firstsubstrate and a second substrate disposed oppositely to each other,between which the above-mentioned oleophobic sealant 10 and thehydrophobic 20 are located. The first and second substrates may actrespectively as an array substrate and a color filter substrate, or ascolor filter on array (COA) substrate and a cover substrate, and viceversa.

By way of example, as shown in FIG. 3, the array substrate or COAsubstrate (with structures such as chips bonded onto the side edge ofits bezel area) is coated with the oleophobic sealant 10 and thehydrophobic sealant 20 and then assembled with the color filtersubstrate or the cover substrate.

For better comprehension of the above-mentioned oleophobic sealant 10and hydrophobic sealant 20 provided in the embodiment of the presentdisclosure, the concept of “contact angle” will be introduced andexplained in the following text. When a liquid drop is formed andstabilized on a solid surface, a contact angle θ of some magnitude willbe formed by the liquid drop at the meeting line of the gas, liquid andsolid phases.

As shown in FIG. 4, the term “oleophobic sealant” means that this typeof sealant has relatively higher repellence against oleiferous liquids,and drops of oleiferous liquids may have contact angels larger than 90°and it is hardly for them to spread out on the surface of the sealant.Relatively, the sealant has relatively higher affinity for water andaqueous liquids with similar dissolvability, so that the aqueous liquidsmay have contact angles smaller than or equal to 90° and it is easilyfor them to spread out on the surface of the sealant. As a result, theabove-mentioned oleophobic sealant may also be referred to ashydrophilic sealant.

Similarly, as shown in FIG. 5, the term “hydrophobic sealant” means thatthis type of sealant has relatively higher repellence against water andaqueous solutions of similar dissolvability, so that drops of aqueousliquids have contact angles larger than 90° and it is hardly for them tospread out on the surface of the sealant. Relatively, the sealant hasrelatively higher affinity for oleiferous liquids, so that theoleiferous liquids may have contact angles smaller than or equal to 90°and it is easily for them to spread out on the surface of the sealant.As a result, the above-mentioned hydrophobic sealant may also bereferred to as oleophilic sealant.

In the above-mentioned display panel provided in the embodiment of thepresent disclosure, two types of sealants are disposed in the peripheralarea of the display panel. The inner layer, i.e. the layer near thedisplay area, is the oleophobic sealant 10. Since liquid crystalscommonly used in liquid crystal displays including biphenyl liquidcrystal, phenylcyclohexane liquid crystal, ester type liquid crystal andthe like, are oleiferous and have no or very low solubility in water,the oleophobic sealant 10 near the display area may reduce the degree ofcontact between the liquid crystals and the oleophobic sealant withoutbeing completely cured, reduce the possibility of being punctured,protect the liquid crystals from being contaminated, reduce defects,such as FLK during display of the liquid crystal display panel, andguarantee display quality. The outer layer, i.e. the layer away from thedisplay area and surrounding the oleophobic sealant 10, is thehydrophobic sealant 20 and can prevent moisture from intruding throughthe sealant to cause corrosion during subsequent usage.

Furthermore, for example and as shown in FIG. 3, the above-mentionedoleophobic sealant 10 includes matrix sealant material 100 and particles101 dispersed in the matrix sealant material 100 with the dispersedparticles 101 having oleophobic first functional groups (not shown inthe figure) on their surfaces. The above-mentioned hydrophobic sealant20 includes matrix sealant material 200 and particles 201 dispersed inthe matrix sealant material 200 with the dispersed particles 201 havinghydrophobic second functional groups (not shown in the figure) on theirsurfaces.

It is to be noted that the above-mentioned matrix sealant material 100and the matrix sealant material 200 may include, but not limited to,resin materials. There are many resin materials to choose, such asacrylic resin, epoxy resin, bisphenol A epoxy resin, polyvinyl butyralresin, diethylene glycol monobutyl ether acetic ester, urethane resincontaining carboxy groups and the like. In addition, the above-mentionedoleophobic sealant 10 or the hydrophobic sealant 20 may also includeinitiator and the like, in this regard, traditional technologies may beused and embodiments of the present disclosure are not limited in anyway.

The so called “particle” refers to a geometric body within a dimensionalrange and having a particular shape. Herein, dimensions of a particlegenerally range in order of magnitude from nanometer to millimeter.Therefore, the above-mentioned dispersed particles 101 or dispersedparticles 201 refer to particles that have relatively small dimensionsand may have many shapes, for example, but not limited to, a sphericalshape.

The dispersed particles (e.g. silicon balls) in the sealant function toprovide some thickness support so as to reduce volume shrinkage of thesealant after being cured, and at the same time, to increase theviscosity of the sealant before being cured, so as to reduce sealantflowage, facilitating stirring and/or screen printing. In addition tohaving the function described above, the dispersed particles in theabove-mentioned oleophobic sealant 10 or hydrophobic sealant 20 providedin the embodiment of the present disclosure also act as carriers forfunctional surface modification of functional groups.

For example, the material of the above-mentioned dispersed particles mayinclude any one of silicon dioxide, silicon, aluminum oxide (Al₂O₃), andthe particles may have a spherical shape to facilitate particledispersing and functional group grafting.

That is, as shown in the view (a) in FIG. 6, an oleophobic modifyinglayer consisting of the oleophobic first functional groups is formed onthe surface of the dispersed particle 101, resulting in a shell-corestructure.

Similarly, as shown in view (b) in FIG. 6, a hydrophobic modifying layerconsisting of the hydrophobic second functional groups is formed on thesurface of the dispersed particle 201, resulting in a shell-corestructure.

It is to be noted that the above-mentioned FIG. 6 is only provided toindicate that a dispersed particle 101 has oleophobic first functionalgroups on its surface, and the first functional groups may be grafted onpart of or the entire surface of the dispersed particle 101, whichincludes, but not limited to, the case indicated schematically in view(a) of FIG. 6) where the first functional groups cover the entiresurface and thus form an oleophobic modifying layer.

In the same way, the above-mentioned FIG. 6 is provided to indicate thata dispersed particle 201 has the hydrophobic second functional groups onits surface, and the second functional groups may be grafted on part ofor the entire of the surface of the dispersed particle 201, whichincludes, but not limited to, the case indicated schematically in theview (b) in FIG. 6 where the second functional groups cover the entiresurface and thus form a hydrophobic modifying layer.

In this way, the surface modifying layer has a thickness in nanometers,no significant effect will be exerted on the dimensions of the dispersedparticles and the line width of TFT wiring in the display panel will notbe additionally increased, resulting in negligible effect on the widthof the bezel of the display panel.

Furthermore, for example, the above-mentioned oleophobic firstfunctional groups include at least one of a hydroxyl group (—OH), analdehyde group (—CHO), a carboxyl group (—COOH) and an amino group(—NH₂).

The above-mentioned hydrophobic second functional group includes atleast one of an alkyl group (—C_(n)H_((2n+1)), where n is a positiveinteger), a vinyl group (—CH═CH₂), a phenyl ring group (—C₆H₅), ahalogen atom (including fluorine (F), chlorine (Cl), bromine (Br),iodine (I) and astatine (At), generally symbolized as —X) and a nitrogroup (—NO2).

The following embodiment is provided to illustrate the process ofmodification using the above-mentioned oleophobic or hydrophobicfunctional groups.

Embodiment 1

Modification by the oleophobic first functional groups: nano-particlesof SiO₂ are used as the dispersed particles 101 in the oleophobicsealant 10. During the grafting process for the functional surfacemodification, 10 grams of nano-particles of SiO₂ are dispersed in 50 mlof HCl solution (the concentration of HCl in water is 10% volume/volume)contained in a 500 ml beaker. After uniformly stirring for 1 hour (h),the solid resultant is separated from the HCl solution and the SiO₂nano-particles are washed several times by deionized water. The solidresultant is placed under a vacuum condition to evaporate the solvent onthe surface, so that oleophobic, i.e. hydrophilic, activated SiO₂nano-particles (SiO₂—OH) are obtained with the above-mentionedmodification method, which has a yield of about 90%.

Embodiment 2

Modification by the hydrophobic second functional groups: nano-particlesof SiO₂ are used as the dispersed particles 201 in the hydrophobicsealant 20. During the grafting process for the functional surfacemodification, 20 ml dehydrated alcohol is placed into a dry beaker, agiven amount of dry nano-particles of SiO₂ are put into the dehydratedalcohol; ultrasonic dispersion is performed on the mixture for 15 min,which is then placed into a 250 ml three-neck flask. Dehydrated alcoholsolution containing a given amount of silane coupling agent (having amolecular formula of C₁₀H₂₂O₄Si, generally marked as KH-570) is then putinto the three-neck flask, which is heated to a certain temperature inwater bath to achieve reflux reaction for 5 h. The solid resultant iscentrifugally separated from the liquid, washed 3 times by dehydratedalcohol, and then placed into an oven at 100° C. to be dried for 10 h,resulting in nano-particles of SiO₂ modified by silane coupling agent.During this process, the hydrophobic functional groups for grafting onthe surfaces are mainly alkyl groups and vinyl groups.

Based on the description above, as shown in FIG. 7, an embodiment of thepresent disclosure also provides a sealant coating device, whichincludes a first sealant supplying container 03 (e.g. a sealant barrel),a second sealant supplying container (e.g. a sealant barrel) and a sprayhead 05. The spray head 05 includes a first accommodation chamber 51, asecond accommodation chamber 52 and a slit opening 53. The first andsecond accommodation chambers 52, 53 are in intercommunication at thearea near the slit opening 53 (resulting in a hybrid gun head as shownin the dashed-line box). The first and second sealant supplyingcontainer 03, 04 are respectively in communication with the ends of thefirst and second accommodation chambers 51, 52 away from the slitopening 53. The first sealant supplying container 03 is used to containthe oleophobic sealant and the second sealant supplying container 04 isused to contain the hydrophobic sealant.

Here, the first and second accommodation chambers 51, 52 are inintercommunication with each other at the area near the slit opening 53,so that a hybrid gun head is formed as shown in the dashed-line box,which can coat two types of sealants at the same time, simplifying thetechnical process.

The above-mentioned device for sealant coating has a simplifiedstructure and needs relatively small modification to the fabricationprocess of an existing coating device. For example, the above-mentioneddevice may be realized by replacing a conventional single spray headwith a spray head having the hybrid gun head and adding an additionalsealant barrel, which is easy to carry out.

Furthermore, for example, as shown in FIG. 7, the above-mentioned devicefor sealant coating also includes a pressure controller to control thefeeding amount of sealant from the first sealant supplying containerand/or the second sealant supplying container.

Based on the description above, an embodiment of the present disclosurealso provides a coating method with the above-mentioned device forsealant coating. The coating method includes: allowing a side of thesecond accommodation chamber of the spray head to face the display areaof the first substrate (e.g. the array substrate or COA substrate asshown in FIG. 3) in the display panel; allowing a side of the firstaccommodation chamber of the spray head to face away from the displayarea; and controlling the spray head to spray the sealant along theperipheral area of the first substrate so as to form the hydrophobicsealant in the peripheral area and on the side near the display area andform the oleophobic sealant in the peripheral area on the side away fromthe display area and surrounding the hydrophobic sealant.

In the above-mentioned display panel provided in the embodiments of thepresent disclosure, two types of sealants are disposed in the peripheralarea of the display panel. The inner layer, i.e. the layer near thedisplay area, is the oleophobic sealant. Since liquid crystals commonlyused in liquid crystal display mainly includes biphenyl liquid crystal,phenylcyclohexane liquid crystal, ester type liquid crystal and thelike, which are oleiferous and have no or very low solubility in water,the oleophobic sealant near the display area may reduce the degree ofcontact between the liquid crystals and the oleophobic sealant beforethe sealant is not completely cured, reduce the possibility of beingpunctured, protect the liquid crystals from being contaminated, reducedefects, such as FLK during display of the liquid crystal display panel,and guarantee the display quality. The outer layer, i.e. the layer awayfrom the display area and surrounding the oleophobic sealant, is thehydrophobic sealant and can prevent moisture from intruding through thesealant to cause corrosion during subsequent usage.

It can be appreciated by those skilled in the art that structuralcomposition of the above-mentioned oleophobic sealant and/or hydrophobicsealant and components of the device for sealant coating provided inembodiments of the present disclosure are not limited by the structuresshown schematically in all of the accompanying drawings in the presentdisclosure, which are provided only to clearly depict structuresassociated with the inventive points. Those structures unrelated withthe inventive points may be implemented with conventional structures andare not or only partially shown in the accompanying drawings.

The described above are only exemplary embodiments of the presentdisclosure, and the present disclosure is not intended to be limitedthereto. For one of ordinary skill in the art, various changes andalternations may be readily contemplated without departing from thetechnical scope of the present disclosure, and all of these changes andalternations shall fall within the scope of the present disclosure.

1. A display panel, comprising: a display area and a peripheral area; anoleophobic sealant provided in the peripheral area on a side near thedisplay area; and a hydrophobic sealant provided in the peripheral areaon a side away from the display area and surrounding the oleophobicsealant.
 2. The display panel according to claim 1, wherein theoleophobic sealant comprises a matrix sealant material and particlesdispersed in the matrix sealant material, the dispersed particles havingoleophobic first functional groups on their surfaces.
 3. The displaypanel according to claim 2, wherein the oleophobic first functionalgroup comprises at least one of —OH, —CHO, —COOH and —NH₂.
 4. Thedisplay panel according to claim 1, wherein the hydrophobic sealantcomprises a matrix sealant material and particles dispersed in thematrix sealant material, the dispersed particles having hydrophobicsecond functional groups on their surfaces.
 5. The display panelaccording to claim 4, wherein the hydrophobic second functional groupcomprises at least one of —C_(n)H_((2n+1)), —CH═CH₂, —C₆H₅, a halogenatom and —NO₂, where n is a positive integer.
 6. The display panelaccording to claim 2, wherein material of the dispersed particlesinclude any of silicon dioxide, silicon and aluminum oxide (Al₂O₃). 7.The display panel according to claim 2, wherein the dispersed particlesare in a spherical shape.
 8. A device for sealant coating, comprising afirst sealant supplying container, a second sealant supplying containerand a spray head, wherein the spray head comprises a first accommodationchamber, a second accommodation chamber and a slit opening, the firstaccommodation chamber and the second accommodation chamber being inintercommunication at the area near the slit opening; and the firstsealant supplying container and the second sealant supplying containerbeing in communication with ends of the first accommodation chamber andthe second accommodation chamber away from the slit opening andconfigured to contain oleophobic sealant and hydrophobic sealant,respectively.
 9. The device for sealant coating according to claim 8,wherein the device for sealant coating further comprises a pressurecontroller to control the feeding amount of sealant from the firstsealant supplying container and/or the second sealant supplyingcontainer.
 10. A coating method using the device for sealant coatingaccording to claim 9, the coating method comprising: allowing a side ofthe second accommodation chamber of the spray head to face the displayarea of the first substrate in the display panel; allowing a side of thefirst accommodation chamber of the spray head to face away from thedisplay area; and controlling the spray head to spray the sealant alongthe peripheral area of the first substrate so as to form the oleophobicsealant in the peripheral area and on the side near the display area andform the hydrophobic sealant in the peripheral area on the side awayfrom the display area and surrounding the oleophobic sealant.
 11. Thedisplay panel according to any one of claim 3, wherein the hydrophobicsealant comprises a matrix sealant material and particles dispersed inthe matrix sealant material, the dispersed particles having hydrophobicsecond functional groups on their surfaces.
 12. The display panelaccording to claim 11, wherein the hydrophobic second functional groupcomprises at least one of —C_(n)H_((2n+1)), —CH═CH₂, —C₆H₅, a halogenatom and —NO₂, where n is a positive integer.
 13. The display panelaccording to claim 12, wherein material of the dispersed particles isany of silicon dioxide, silicon and aluminum oxide (Al₂O₃).
 14. Thedisplay panel according to claim 13, wherein the dispersed particles arein a spherical shape.
 15. The display panel according to claim 2,wherein the hydrophobic sealant comprises a matrix sealant material andparticles dispersed in the matrix sealant material, the dispersedparticles having hydrophobic second functional groups on their surfaces.16. The display panel according to claim 4, wherein material of thedispersed particles include any of silicon dioxide, silicon and aluminumoxide (Al₂O₃).
 17. The display panel according to claim 4, whereinmaterial of the dispersed particles include any of silicon dioxide,silicon and aluminum oxide (Al₂O₃).
 18. The display panel according toclaim 5, wherein material of the dispersed particles include any ofsilicon dioxide, silicon and aluminum oxide (Al₂O₃).